UUID Generator

What Is a UUID?

A UUID (Universally Unique Identifier) is a 128-bit value formatted as 32 hexadecimal digits displayed in five groups separated by hyphens (e.g., 550e8400-e29b-41d4-a716-446655440000). UUID v4, the most common version, is randomly generated and has an astronomically low probability of collision — making it ideal for unique identifiers in distributed systems.

How Do I Generate a UUID?

Click the Generate button and the tool creates a random UUID v4 using the Web Crypto API for cryptographic randomness. Copy it with one click. You can also generate multiple UUIDs in bulk for batch operations. All generation happens in your browser — nothing is sent to a server.

When Do Developers Use UUIDs?

UUIDs are used as primary keys in databases, unique identifiers for API resources, correlation IDs in distributed logging, session identifiers, file names for uploaded content, and transaction IDs in payment systems. They are preferred over sequential integers when you need IDs that do not reveal information about the total count or creation order.

Are UUIDs Truly Unique?

For all practical purposes, yes. A UUID v4 has 122 random bits, which means there are about 5.3 × 10^36 possible values. The probability of generating two identical UUIDs is so small that it would take billions of UUIDs generated every second for decades to have even a 50% chance of a single collision.

What Are the Different UUID Versions?

UUID v1 is based on timestamp and MAC address (can expose hardware info). UUID v3 uses MD5 hash of a namespace and name. UUID v4 is randomly generated (most popular, used by this tool). UUID v5 uses SHA-1 hash of namespace and name. UUID v7 (newest) is time-ordered with random bits, combining the sortability of v1 with the privacy of v4.